The decay of wood and other cellulosic materials by fungi, and the consumption of wood by termites, cause significant economic loss. Until recently, the most widely used wood preservative has been chromated copper arsenate (CCA). However, production of CCA for use in residential structures was prohibited as of January 2004 due to issues raised concerning the environmental impact and safety of arsenic and chromium used in CCA-treated lumber. As CCA replacements, arsenic-free and chromium-free wood preservatives are sought. Retention in treated wood of copper and other metal ions that are effective fungicides is a challenge. Metal salts are generally water soluble and rapidly leach from treated wood, which causes loss of the preservative function.
Wood rotting fungi are typically either white-rot or brown-rot basidiomycetes. Brown-rot fungi are the most destructive wood rotting organisms, though they make up only 7% of all wood rotting basidiomycetes (Gilbertson and Ryvarden (1986) North American Polypores, Abortiporus-Lindtneria, Vl. Gronslands Grafiske A/S, Olso, Norway). The brown-rot fungi are generally tolerant of copper, the typically used wood preservative, which is effective against the white-rot fungi. Thus, compounds active against brown-rot fungi are needed in wood preservatives.
Ibuprofen has been shown to be toxic to many different isolates of brown-rot fungi [Clausen, Report #IRG/WP 10160, (1996) USDA Forest Products Lab., Madison, Wis.]. In addition, ibuprofen has been found to be toxic to termites (Connick et al, (2001) Environmental Entomology, v 30, p 449-455). The potential value of ibuprofen as a wood preservative, however, would be limited by the fact that is only slightly soluble in water, so solutions with effective wood preservative concentrations cannot be readily made.
Thus there is a need for ibuprofen-containing wood preservatives that can penetrate wood, and yet be fixed in the wood to provide long-term protection.